1. Field of the Invention
The present invention relates to a method for manufacturing semiconductor devices having an etching process.
2. Related Background Art
Various forms of etching have been adopted for the manufacturing of semiconductor devices.
For example, when a pressure sensor or cantilever is fabricated on a silicon substrate by micromachining, a jig is used as shown in FIG. 4 to etch by immersion in an alkaline etching solution such as an anisotropic aqueous KOH solution.
In FIG. 4, 451 is an Si substrate to be etched, 452 is an anti-etching mask, and 453 is a portion (pattern) for undergoing the etching. An etching sample 451 is laid on a sample carrier 460 of a jig lower lid 458.
Then, an O-ring seal 454 is placed on the upper face of sample 451, on which a jig upper lid 455 having a groove for the O-ring 454 formed is placed. The jig upper lid 455 has a window 456 through which the etching solution enters. The window has a dimension smaller than the O-ring 454, and slightly larger than the pattern 453. Also, the upper lid 455 and the lower lid 458 are sealed by another O-ring 457.
By using such a jig when immersed, the sample 451 has direct contact with the etching solution only in the area where etching is desired. Accordingly, even if there is any Al wiring immersed in the etching solution on the back face side (sample carrier side) of the sample 451, for example, it is never corroded by the etching solution.
However, in etching in the above manner, an excess portion of the sample 451 for disposing the O-ring 454 was required outside of the pattern 453 desired to be etched.
For example, when a Si chip mounted with a semiconductor integrated circuit is subjected to etching, the increased chip area reduces the number of chips to be obtained from a wafer, thus directly increasing the chip costs.
Further, additional time for incorporating a sample into the jig is necessary. The O-ring 454 and the sample 451 must be placed in correct alignment. When it was incorporated only manually without the use of any precision apparatus, the alignment was not very precise, so that a further excess portion for absorbing an alignment error was required.